Degradation behavior in soil and mechanical properties of bagasse monoesters with different acyl chain lengths and residual hydroxy contents

Biomass plastics with biodegradability and suitable mechanical performance are needed to replace persistent synthetic plastics derived from fossil fuels. Lignocellulosic agricultural wastes, such as sugarcane bagasse, are promising renewable resources that offer better thermal processability when their abundant hydroxy (OH) groups are substituted with acyl groups, particularly those with longer chain lengths. However, excessive chemical modification can impair the inherent biodegradability of lignocellulose and weaken the resulting plastics. In this study, the acyl group was optimized to a decanoyl (De, C=10) group, which was the most effective in lowering the melt flow temperature of the fully substituted bagasse monoester to improve thermal moldability. The bagasse decanoate (BagDe) series were synthesized using different amounts of vinyl decanoate (VDe) ranging from 3 to 0.4 molar equivalents to the total OH content of bagasse, and their thermal/mechanical properties and degradability in soil were examined. BagDe synthesized with more than 0.6 equivalents of VDe could be hot-press molded, while the increased residual OH content improved the water uptake, degradation rate, and tensile strength. These findings indicate the potential applications of lignocellulose-based biodegradable plastics, such as agricultural mulch films.